Miller, I doubt we'll resolve this one, because you're moving faster than Brister's moving targets. You now go back to the loads being balanced to "their bores", which is VERY different that your "balance one another" phrase, which apparently is now somewhere distant in your rearview mirror (where it belongs). The previous sentence in Brister's book holds the key: whatever the mathematical relation between the length and weight of shot column relative to bore diameter (and other factors), the result is "highly efficient for the shot load it throws". In other words, balanced in terms of the patterns they deliver.
And you're now doing backwards math. I agree that a load which patterns 89% at 35 yards is almost certainly going to pattern better than 70% at 40 yards. So, let's follow the logic on that one and arrive at what it means: That particular choke and load is highly efficient; more efficient than your average full choke, regardless of gauge or load, since the standard for full choke at 40 yards is only 70%. So, in essence, you've come round to agreeing with Brister that, in fact, the 28 is indeed "highly efficient for the shot load it throws"--because otherwise it would not produce patterns like that. Particularly when it has to deal with more potential shot deformation (coming out of that skinny little bore) than do the larger gauges, all else being equal.
The art of the whole thing is that some loads in some gauges, for whatever reason--likely having nothing at all to do with a "balanced" load, or a "square" load--simply perform better than one would expect them to, going purely on mathematics and theory. it's a bit like choke in that regard. Squeeze the barrel a little, the pattern gets a little tighter. Squeeze it a little more, it gets a little tighter. Squeeze it too much, and it ceases to get tighter, and at a certain point may get looser. Before Kimble or Pape or whomever else came up with that concept, no one had any idea it would work that way. And until they constricted the bore too much, they had no idea that there was any such thing as too much constriction. Now, I expect there's a scientific explanation for it. But the discovery was based on art: shooting targets without knowing what the results would be. Pretty much like shooting certain loads to see which ones work better in which gauges and chokes. Balanced load or square load doesn't get us there. Playing around with shells and shooting patterns does. That's art. All the theories and math in the world won't get you there . . . except those theories and math derived from the art that's evolved from 150 years or so of playing around with chokes and loads. What science there is, in those areas, came AFTER a whole lot of trial and error and experimentation. No theory I know of said "3/4 oz is the right load for the 28ga", or "A 1 1/4 oz load will work particularly well in a 12ga". All reached by trial and error. Would've been a whole lot easier if someone with a pencil and paper could have told shooters those things based on whatever theory they might have had . . . but that's not the way it worked.
